1 biofuels biofuels: release prevention, environmental behavior, and remediation sponsored by:...

1

Biofuels

Biofuels: Release Prevention, Environmental Behavior, and Remediation

Sponsored by: Interstate Technology and Regulatory Council (www.itrcweb.org) Hosted by: US EPA Clean Up Information Network (www.cluin.org)

Welcome – Thanks for joining this ITRC Training Class

2

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Copyright 2013 Interstate Technology & Regulatory Council, 50 F Street, NW, Suite 350, Washington, DC 20001

3ITRC (www.itrcweb.org) – Shaping the Future of Regulatory Acceptance

Host organization Network

• State regulators All 50 states, PR, DC

• Federal partners

• ITRC Industry Affiliates Program

• Academia• Community stakeholders

Disclaimer

• Full version in “Notes” section

• Partially funded by the U.S. government

ITRC nor US government warrantee material

ITRC nor US government endorse specific products

• ITRC materials copyrighted

Available from www.itrcweb.org

• Technical and regulatory guidance documents

• Internet-based and classroom training schedule

• More…

DOE DOD EPA

4

Meet the ITRC Trainers

Mike MaddiganPennsylvania Department

Environmental ProtectionHarrisburg, [email protected]

David TsaoBPNaperville, IL630-420-5147 [email protected]

Denice NelsonARCADIS-US, Inc.Minneapolis, MN612-386-4618denice.nelson

@arcadis-us.com

Mark TosoMinnesota Pollution

Control AgencySt. Paul, MN651-757-2158mark.toso

@state.mn.us

5

Biofuels and the Environment

What are biofuels and why are they important? Are there equipment compatibility issues

associated with biofuels? How do biofuel releases impact the

environment? Do biofuels behave differently in the

environment than petroleum-based fuels? How should biofuels releases be cleaned up?

6

What You Will Learn

Scope of potential environmental challenges Differences between biofuel and petroleum fuel

behavior Biofuel supply chain, potential release scenarios,

and release prevention How to develop an appropriate conceptual model

for the investigation and remediation of biofuels Appropriate investigation and remediation

strategies How to assess the behavior of new biofuels

when alternatives come on the market

7

Training Roadmap

Introduction Releases Fate and Transport Q&A Session #1 Site Investigation Long-Term Response Strategies Summary Q&A Session #2

= hypothetical case study

8

CapillaryFringe

Aquifer

VadoseZone

DispensingStation

Our Hypothetical Case Study

UndergroundStorage TankSystem (UST)

DispenserSystem

GroundwaterFlow Direction

9

What Are Biofuels?

For the purposes of this training, the term biofuel is applied to liquid fuels and blending components produced from renewable biomass feedstocks used as alternative or supplemental fuels for internal combustion engines.

10

Important Terms

Denatured Fuel Ethanol (DFE) – fuel ethanol made unfit for beverage use by the addition of a denaturant; also called E95.

FAME (Fatty Acid Mono-alkyl or Methyl Esters) – Transesterified oils derived from vegetable oils or animal fats, blended with or used in place of conventional diesel fuels.

Biofuel Blend – Mixture of biofuel and conventional petroleum-based fuel.

Conventional Fuel – A mixture of compounds, called hydrocarbons, refined from petroleum crude, plus additives to improve its stability, control deposit formation in engines, and modify other characteristics.

11Why be Concerned with Biofuel Releases?

Catastrophic impact of large releases• Large releases from tank

car train derailments

• Massive fires Smaller releases

• Slow leaks can go undetected (such as in storage tanks)

• Large volume - severe environmental impacts

2009 train derailment in Rockford, IL resulting in 435,000-gallon DFE release.

Scorched rail cars after fire in the Rockford, IL release.

Photos from NTSB

12

Petroleum vs. Biofuel Releases

Behave differently in the environment• Site characterization and

remediation strategy

• Safety risks

• Potential release points

For more info on LNAPL training go to http://www.itrcweb.org

13

Federal Renewable Fuel Mandates

Energy Policy Act of 2005• First Renewable Fuel Standard (RFS) program

• Required 7.5 billion gallons of renewable fuel to be blended into gasoline by 2012

Energy Independence & Security Act of 2007• Renewable fuel requirements increased

9 billion gallons (2008) 36 billion gallons (2022) Additional alternative fuel objectives for federal

Alternative Fuel Vehicle (AFV) fleets

14State Renewable Fuel MandatesTable 1-3

NM

MTWA

OR MN

MO

LAFL

PA MA

HI

15

International Mandates

European Union• Directive 2003/30/EC• Promotes biofuels use in

transportation sector• Proposes non-mandatory

biofuels use targets Brazil

• Has required the use of biofuels since 1976

16 ITRC Guidance: Biofuels: Release Prevention, Environmental Behavior, and Remediation

1. Biofuel basics

2. Release prevention and response planning

3. Fate & transport (F&T) of biofuels in the environment

4. Characterizing release sites

5. Long-term response strategies

6. Stakeholder concerns

17

What is Not Covered

Vegetable oils, recycled greases, and fuels indistinguishable from petroleum-based fuels

Air quality Sustainability Detailed information on

manufacturing processes End-user considerations Biofuel policies Fuel additivesNO

T IN

CLUDED

18Applying the ITRC Document Before a Release

Release prevention• Ensure materials

compatibility

• Update best management practices

Release response planning• Fire/explosion threats

• Rapid containment

19Applying the ITRC Document After a Release

Site characterization, sampling, F&T modeling• Physical, chemical, and biological properties• Developing Site Conceptual Model (SCM)

Long-term responses• Determining remediation strategy• Assessing hazards and risks

Stakeholder concerns• Location of incident• Timing of response

Emerging biofuels• Multi-media evaluation process

20Ethanol Fuel Blends (Table 1-1)

Fuel Description ASTM Standard

E85 A commercial trade name representing an alternative fuel consisting of 70%–85% DFE by volume as defined in the EPAct of 1992

No adopted standard

Ethanol fuel blends for flexible-fuel vehicles

Fuel produced for use in ground vehicles equipped with flexible-fuel spark-ignition engines containing 51%–83% ethanol; may be referred to at retail as “ethanol flex-fuel”

D5798-11

Intermediate ethanol blends

Intermediate blends of DFE and gasoline >E10 and <E51

No adopted standard

E10 Gasoline with up to 10% DFE by volume D4814 (standard for gasoline)

“Neat Ethanol” (E100) is non denatured ethanol

21Biodiesel and Biodiesel Blends(Table 1-2)

Fuel Description ASTM Standard

B100 Biodiesel fuel blend stock; legally registered as a fuel and fuel additive with USEPA under Section 211(b) of the Clean Air Act

D6751-11

>B20 to <B100

A blend of petroleum-distillate and biodiesel fuel that contains between 21% to 99% biodiesel

No standard adopted

>B5 to B20A blend of petroleum-distillate and biodiesel fuel that contains between 6% to 20% biodiesel

D7467-10

Up to B5Fuel blends of up to 5% biodiesel fuel are considered a fungible component of conventional petroleum-based diesel fuel

D975 (same as petroleum standard)

“Neat Biodiesel” is biodiesel not blended with petroleum-based diesel and is designated as “B100”

22Biofuel Production Projections(Figures 1-1 and 1-2)

World Ethanol Production Projections

(millions of gallons)

World Biodiesel Production Projections

(millions of gallons)

35,000

25,000

15,000

2010

2012

2014

2016

2018

6,000

5,000

4,000

3,00020

10

2012

2014

2016

2018

23Opportunities to Use this Document in Your State

Connection to your state vapor intrusion regulations or guidance• Fate & transport modeling

• Indoor air modeling Equipment compatibility requirements

• Storage tank programs

• Bulk transport requirements Facility response plans

• Emergency response

• Spill Prevention Control and Countermeasures (SPCC) plans

24

Training Roadmap


25Biofuel Releases(Section 2)

Evaluated based on the differences between petroleum and biofuel

supply chains

Prevention

Release Scenarios and Frequencies

Release Causes

This section will cover

Emergency Response Planning

26Petroleum vs. Biofuel Supply Chains(Combined Figures 2-1 and 2-2)

ManufacturingFacility

Bulk Depot /Supply Terminal

DispensingStation

Transport Distribution

AST

Piping & Manifold

Loading Rack

AST

Piping & Manifold

Unloading / Loading Rack

Truck

Truck

Rail

Barge

Pipeline

UST System

Product Piping

Dispenser

UST

Refinery –OR–(Blended)(Bulk)

Co

mp

on

ents

27Release Scenarios and Incidents (Section 2.1)

If all bulk gasoline and diesel currently transported was used to produce E10 and B5, then bulk biofuels transport needs would be:• 1,250 tanker trucks,

• 415 railcars, or PER DAY

• 20 tank barges

Potential Volume Incident Frequency

Railcars: ~25,000 to 30,000 gallons per railcar; unit trains 70-100 cars

2,000 derailments per year (severity not specified)

Tanker trucks: ~8,000 to 10,000 gallons per truck

1,000 road accidents per year (1 in 25,000 deliveries)

Tank barges: ~420,000 to 630,000 gallons per barge typical

2.16 gallons spilled per 1 million gallons moved

Volume and Incident Frequencies (Table 2-1):

Truck

Transport

Distribution

Truck

Rail

Barge

Pipeline

28Release Causes (Section 2.2)

DispensingStation

UST System

Product Piping

Dispenser

UST

Leak Detection Issues, Release Causes (Table 2-2):

Equipment Detection Causes

Underground Storage Tank (UST) System

Small volume or chronic releases may not be detected if commercial leak detection equipment is incompatible

Incompatible materials; solvent nature of biofuels scouring sediment, sludge, rust, and scale built up in tank previously storing conventional fuels

Acute, large volume releases detected through automated volume reconciliation accounting

Dispenser System

Small volume or chronic releases detected through standard inspections

Incompatible materials; filters plugging due to insufficient rate of changeouts

29Selected Biofuel Release Information (Table D-2, Appendix D)

See Appendix D: fate and transport evaluation (Section 3), analytes investigated (Section 4), and response activities conducted (Section 5)

Site FuelVolume in gallons

(Section 2.1)Causes

(Section 2.2)

PNW Terminal, OR DFE 19,000 AST release

Maxville, OntarioBalaton, MNSouth Hutchinson, KSCambria, MNStorrie, CARockford, ILWilliams County, OH

DFE 26,00060,00028,00025,00030,000

55,000 – 75,00080,000

Derailment

Wood River, NE DFE 20,000 Loading railcar

Rice, MNHastings, MN

E85 700800

UST release

St. Paul, MN Biodiesel 29,000 AST release

30Release Prevention (Section 2.3)

Compatible materials and equipment • Plastics, polymers, and elastomers

• Metal components and solders

• Commercial leak detection equipment Management practices

• Changing out filters more frequently can prevent clogging issues

• Proper Operations & Maintenance and frequency on leak detection equipment prevents undetected releases

Appendix B (checklist) provides guidance on compatibility of UST systems for biofuels

ITRC, Biofuels-1, Figure 2-7

ITRC, Biofuels-1, Figure 2-5

31Emergency Response Planning (Section 2.4)

Applicable plans • Spill Prevention Control and Countermeasures

(SPCC) regulations (40 CFR 112) • Facility Response Plans (FRP)

Additional Emergency Response considerations• Common fire-fighting foams – less effective • Appropriate foams – less available• Sorbent booms – miscibility, sorption, etc.• Impacts to sensitive receptors – oxygen demand,

biodegradability, etc.

32

Our Case Study: The Release

Release Cause (Section 2.2)E85 scoured the sludge, rust, sediment, & scale

Release Volume (Section 2.1)10,000 gallons E85 released from a UST that was switched from storing E10

Release Prevention (Section 2.3)Guidance on converting tanks to E85 NOT used

33Biofuel Releases Summary(Section 2)

Biofuel releases will occur somewhere along the supply chain Current case studies (Appendix D) indicate they occur more

often in association with bulk transport or during storage Frequency is likely to increase as storage and handling

increases Root causes are often materials compatibility and

management practices associated with equipment Can be addressed to prevent releases such as using the tank

conversion checklist (Appendix B) Resources for emergency response preparedness are also

available

34

Training Roadmap


35Fate and Transport(Section 3)

Effects on microbial communities and by-

product formation

Biofuel Properties

Surface and subsurface

behavior

Use of the hypothetical case study to help illustrate key points

This section will cover:

Impacts on petroleum hydrocarbons and

NAPL

36

Solubility (mg/L)

Henry’s Law Constant (unitless)

Vapor Pressure (mm Hg)

Biodegradation Potential

Implications

Ethanol Infinite 2.1E-4 to 2.6E-4

59 Aerobic: hours to days Anaerobic: days to weeks

Readily partitions to water and dilutes according to availability. Rapidly biodegradable

Benzene 1,800 0.22 75 Aerobic: days to months Anaerobic: years

Readily partitions to vapor phase from NAPL and from water

Properties of Selected Fuel Components (Table 3-1)

Summary of some of the more pertinent properties of biofuels and reference compounds (benzene and diesel)• Provides a generalized summary of implications relating to these

properties

• Expanded property table available in Appendix C of the document Table excerpts provided for the E85 case study

37Behavior in Surface Spills (Section 3.5.1 and 3.5.2)

Initial fate can be controlled by• Vaporization• Ignition and consumption by fire• Surface drainage • Surface water dilution

Immediate short-term impacts on surface water biota• Aquatic species toxicity (Section 1.6)

Ethanol and isobutanol: aquatic toxicity values range from 1,000 mg/L to > 14,000 mg/L

Biodiesel: numerical values currently not available (area of research)

• Dissolved oxygen depletion Can result in detrimental impacts to aquatic life (i.e. fish

kills)

38

Groundwater flow direction

Dissolved phase plume

Aq

uifer

Un

saturated

zon

e

Capillary fringe

Dis

solu

tion

NAPLbody

Volatilization

Primary source (short term)

Trapped and sorbed residual

Groundwater source (longer term)

Behavior in the Subsurface: Petroleum Hydrocarbons (Figure 3-1)

ITRC LNAPL guidance and training available for additional information on LNAPL distribution – www.itrcweb.org/LNAPLs

39

(collapsed) capillary fringe

capillary fringe

aquifer

Conventional gasoline (E0) E10 DFE

Dissolution to groundwater

Behavior in the Subsurface: Ethanol Blends (Figure 3-5)

Ethanol blends behave differently than low solubility biofuels or petroleum compounds• Ethanol fraction will partition into soil moisture present within the vadose

zone and capillary fringe• Once in contact with groundwater, will migrate• Likelihood of ethanol reaching groundwater is dependent on release

scenario (large spills more likely to reach water table)

High permeability water-filled lens

Pore water containing ethanol

Immobile gasoline phase

40Potential Media Impacts by Equipment Type (Table 3-2)

Table objective: provide information regarding potential release points, release volumes and media that can be affected by release

Example for E85 case study (UST release)

Equipment Type Potential Media Impacts

Underground storage tank systems (Section 2.2.5)

• Dispensing stations• May be present at

manufacturing facilities and bulk depots/supply terminals

• Surrounding backfill and soil in the UST “pit”• Groundwater impacts depend on the proximity of the

water table to the UST as well as a sufficient driving force to cause the biofuel to percolate to depth

• If groundwater is impacted, cosolvency issues may be present if historic petroleum releases have occurred at the same location

41Biochemical Oxygen Demand (Section 3.3.2.2)

Release of biofuel into an aqueous environment will result in rapid consumption of dissolved oxygen (DO)

In groundwater, rapid biodegradation will induce anaerobic conditions Dead paddlefish resulting from a

release of Wild Turkey Bourbon

42

Figure 3-2. Major routes of the anaerobic fermentation of ethanol

Methane

Methane

Acetyl CoA Butyryl CoA

AcetoacetylCoA

EthanolCO2

H2 Butyrate

Butanol

Acetate

Acetone

CO2

CO2

Biofuel Biodegradation(Figure 3-2)

Biofuels more readily biodegradable

43

Factors Affecting Biodegradation

Inhibition of biological degradation at high concentrations (6% - 10% ethanol)

Rate affected by• Available electron acceptors

• Nutrients

• pH (optimal = 6-8) Production of volatile fatty acids during metabolism

can lower pH

44Methane Hazards(Figure 3-4)

Methane is aflammable gas• Lower explosive limit (LEL)

= 5% in atmosphere

• Upper explosive limit (UEL) = 15% in atmosphere

LEL equivalent concentration in groundwater • 1 - 2 mg/L

• Dependent on temperature

Methane

Capable of forming explosive mixtures

with air

Not capable of forming explosive mixtures with air

Explosive

Mixtures which cannot be produced from methane

and air

Oxy

gen

0

4%

8%

12%

16%

20%

4% 8% 12% 16% 20%

Relationship Between Quantitative Composition and Explosivity of Mixtures of Methane and Air

0

Figure source: 30 CFR 57.22003

45Generation of Methane(Figure 3-3)

Methanogens utilize acetate and hydrogen• Partitioning between dissolved

and gaseous methane concentrations

• Dissolved methane concentration dependent on groundwater temps

Delays (months to years) in methane production have been observed in both lab and field studies

Methane soil gas may undergo attenuation in the vadose zone

Dissolved Methane (mg/L)

Est

imat

ed S

oil

Gas

Met

han

e (%

)

Temperature (70oF)Temperature (45oF)

0 10 20 30

100

80

60

40

20

0

46Preferential Biodegradation of Biofuels Over COCs (Section 3.4.3 and 3.4.4)

Readily degradable nature of biofuels can result in preferential biodegradation of biofuels over COCs

Plume elongation expected to be temporary Elongated plumes may have shorter lifetimes

because of lower concentrations of petroleum hydrocarbons and buildup up biomass

Redox changes in the subsurface may lead to changes in the mobilization of metals

47Enhanced Solubility of Petroleum(Section 3.4.1)

Some biofuels can act as cosolvent • High concentrations (> 20% ethanol)

• May occur within capillary fringe

• Unlikely to occur in groundwater Releases of highly soluble biofuels (e.g. ethanol)

onto prior hydrocarbon releases• May result in mobilization of pre-existing residual

separate phase hydrocarbons

• Section 3.4.2

48

Our Case Study: Fate & Transport

Media impacts to vadose zone, capillary fringe and groundwater• Capillary fringe can

act as a lingering source area for ethanol

Groundwater will become anaerobic, possibly leading to methane generation

CH4

49

Fate and Transport Summary

Property differences between biofuels and petroleum fuels influence fate and transport in the environment

Highly soluble biofuels readily partition into water Biodegradable nature of biofuels significantly impacts

dissolved oxygen concentrations Ethanol can be retained in the capillary fringe (lingering

source) Cosolvency effects likely limited to capillary fringe and large

E95 releases Potential for significant methane generation Temporary plume elongation

50

Training Roadmap


51

Training Roadmap


52Site Investigation(Section 4)

Analytical Methods

RiskDrivers

Monitoring

Use of the hypothetical case study to help illustrate key points


Site Closure Considerations

CH4

53

Risk Drivers for Site Investigation

Surface water• Ethanol can not be recovered due to solubility; biodiesel can be

recovered like petroleum

• Dissolved oxygen depletion – risk to aquatic species a significant new concern

Vadose zone• Explosive risk from increased methane production – NO ODOR

• Potential increased vapor intrusion (VI) risk for petroleum VOCs

Groundwater• Risk to drinking water supplies due to plume elongation

• Biofuel degradation can produce taste and odor issues in drinking water supplies

54July 2008 – Lanesboro, MN3,000 gals E95

55Our Case Study: Site Investigation (Section 4)

Site investigation strategy:

• Dependent on age, volume, composition of release

• Potential risk receptors

Case study:

• Recent E85 spill

• Dispensing station building and surrounding residential area

CH4

56

Site Investigation – What’s Different

Different chemical and physical properties of biofuels require changes to investigation design• Monitoring well screen length and type

• Additional analytical parameters

Additional vapor risk assessment for VOCs and methane (if receptors are present)

Time factor• Longer monitoring duration needed to assess risk

57

Methane Monitoring (Section 4.1.1)

Biofuels have the potential to generate significantly more methane than petroleum

Initial evaluation should determine if explosive conditions exist

Methane appearance may not be immediate, suggesting extended monitoring when receptors are present• Low or no initial methane may not mean no future risk• May appear without detection of source biofuel

Subsurface methane may be sampled in:• Soil gas using push probes or vapor points• Groundwater using push probes or wells for dissolved

methane

58

Methane Monitoring (Section 4.1.1)

Groundwater • Generally more reliable than soil gas for detection

• Well screen lengths may affect concentrations

• Must closely follow QA/QC sampling procedures

• Methane is easily lost during sampling

• Levels above 25 mg/L indicate saturated levels where ebullition (bubbling) may be occurring

Soil gas• Sampling points and procedures same as VOCs (ITRC

2007, Vapor Intrusion Pathway: A Practical Guideline)

• If potential receptors are present at least one vapor monitoring point should be placed in the release area

59November 2006 - Cambria, MN25,000 gals DFE (E95)

60Delayed Methane Generation: Cambria, MN Case Study July 2007 (Appendix D)

61Delayed Methane Generation: Cambria, MN Case Study December 2007 (Appendix D)

62

Ethanol Monitoring (Section 4.1.2)

Vadose zone• Soil gas monitoring same as VOCs

• Soils can be sampled using standard VOC methodology

Capillary fringe• Lysimeters have been used, but sampling capillary fringe not

necessary

Groundwater• Shorter monitoring well screens recommended to capture ethanol

draining, and/or leaching from the capillary fringe

• Multi-level wells may be needed

• Detection of ethanol in groundwater should not be used alone for methane risk assessment

63

Cambria, MN Case Study

Groundwater

Capillary fringe

Ethanol

Aq. Ethanol

MW-1 (10’ screen) ND

MW-20 (5’ screen) 5,300,000 ug/L

Soil Sample6,340,000 ug/kg

Note: Not in ITRC document

64

Biodiesel Monitoring (Section 4.1.3)

Biodiesel forms a LNAPL on groundwater• Wire wrapped screens are recommended to help facilitate the

entry of higher viscosity biodiesel LNAPL into monitoring wells

• TarGOST (LIF) has been shown to effectively map B100 NAPL

No standard analytical methods for biodiesel in soil or groundwater exist but surrogates can be used• Bugs immediately hydrolyze FAMEs to fatty acids

• TOC/DOC and COD to quantify dissolved fraction in groundwater

• TOC can also be used to quantify biodiesel in soil

• Degradation products (e.g. short chain fatty acids)

• Surrogates do not directly quantify the concentration of biodiesel, but are useful to evaluate groundwater impact and methane generation potential

65

Biodiesel Monitoring (Section 4.1.3)

Biodiesel (B100) produces a lot of methane (and CO2)

Like ethanol ebullition (bubbling) may increase methane risks, and VI risks for blended fuels

1.4L FAME → 662 L methane

Biodiesel also has a taste/odor/appearance impact on water quality

Petroleum fraction of blends may be the risk driver for biodiesel blends; however methane may still be an issue for higher percentage blends

66

Surface Water Monitoring (Section 4.1.4)

Depletion of dissolved oxygen and the affect on aquatic life is primary concern with soluble biofuels (e.g. ethanol)

DO may be measured directly in the field COD, DOC and/or TOC may be used to assess the

potential oxygen consumption load

67Field Screening Methods (Table 4-1)

Analyte Environmental Media Analytical Methods

Field Methods

Methane Soil Gas Infrared landfill gas meter

Methane (LEL) Soil Gas Explosimeter

Ethanol/butanol Soil Gas Photoionization detector

DO Surface Water Field meter, kit, or titration

BOD Surface Water Field meter or kit

Table for Sampling and Analytical Methods (Table 4-1)

68Analytical Laboratory Methods (Table 4-1)

Analyte Environmental Media Analytical Methods

Methane Soil Gas USEPA 3C; ASTM D1946

Dissolved Methane Groundwater RSK-175

Acetate Groundwater Ion chromatography, other

DOC/TOC Surface Water, Soil, Groundwater

Standard Method 5310C; ASTM D513-6; USEPA 415.3

BOD/COD Surface Water USEPA Methods 405.1 (BOD); 410.1 #DR/3000 (COD), or similar

Ethanol/butanol Soil USEPA 8260B

Ethanol/butanol Soil Gas USEPA Method TO-15

Ethanol/butanol Groundwater USEPA 8260B; USEPA 8260; USEPA 8015C; USEPA 8261A

69

Our Case Study: Site Investigation

Install vapor point near receptor

Shorter-screened wells in source area

Monitoring for additional parameters

CH4

Monitor soil gasnear receptor(CH4, VOC)

Use shorter screened wells in

source area

Monitor the groundwater

(diss. CH4, EtOH, VOC, Acetate

70Site Investigation Summary(Section 4)

Methane in soil gas = likely risk driver Physical properties of biofuels may require some changes

to a site investigation design, such as monitoring wells Sampling for additional parameters will likely be required Additional field screening equipment may be required Additional VI monitoring may be required due to

• Stripping of petroleum VOCs from groundwater and advection of petroleum vapor by methane and other biogenic gases

• Methane exerts a large oxygen demand which can allow petroleum vapors and methane to migrate further

Site investigation of other or new biofuels should be based on the physical, chemical, and biological properties of the biofuel

71

Site Closure Considerations

Was the site investigation adequate for a biofuel release?

Have all groundwater and vapor risks been identified?

Are degradation products still present in groundwater (e.g. methane, acetate)

Has monitoring adequately accounted for delayed methane generation?

If elevated risks and hazardous conditions exist, remediation may be required

72

Training Roadmap


73Long-Term Response Strategies(Section 5)

General considerations for remediation

Risk management

Remedial selection Use of the hypothetical case

study to help illustrate key points


CH4

74Our Case Study: Long-Term Response Strategies (Section 5)

Requires consideration of:• Type of biofuel

• Extent and magnitude of the release

• Regulatory threshold for a COC(s)

• Risk to identified receptors

Case study:• E85 spill

• Media impacted:

• Vadose zone

• Capillary Fringe

• Groundwater

• State regulations applicable to gasoline components

• Dispensing station building and surrounding residential area

CH4

75Generalized Framework (Figure 5-1)

Site Conceptual Model/Site

Characterization

Yes

No Further Action/Site

Closure

No

Implement closure monitoring and/or

controls

Yes

Yes

No

Active Remedy

Yes

No

No

Yes

Sections 3 and 4

Sect 5.1

Sect 5.2.1 Sect 5.3

Sect 5.3.3

Sect 5.2.2

Sect 5.4

Meetremedial

endpoints?

Riskacceptable or

manageable w/ controls?

Above regulatory

threshold and/or a potential hazard

exists?

Meet closure

requirements?

76Risk Management(Section 5.2.1; Table 5-1)

Management of risk through long-term monitoring Controls (institutional or engineering)

• Provide protection from exposure to contaminant(s)that exist or remain on a site

Benefits Limitations

Dissolved biofuel is readily biodegradable without additional enhancement

• High concentrations of some dissolved biofuel constituents (i.e., ethanol) can be toxic to microorganisms

• Delayed biodegradation of more recalcitrant contaminants via preferential biodegradation of the biofuel

• Does not address immediate risks• High potential for methane generation• Does not address LNAPL, although microbial processes can enhance dissolution in groundwater

• Surface water may become anoxic, impacting aquatic species and habitat

Implement closure monitoring and/or

controls

77Selection of Remedial Technology(Tables 5-2 and 5-3)

Active remedy• Eliminate or reduce the remediation driver or COC

Remedial technologies • Soils/Sediment (Table 5-2)• Groundwater/Surface water (Table 5-3)

Categorized as in situ or ex situ Subdivided within each category by dominant remedial

mechanism• Biological technologies (e.g. enhanced aerobic biodegradation)• Chemical (e.g. chemical oxidation)• Physical (e.g. soil vapor extraction)

Provides discussion on overall benefits and limitations of each technology to help guide selection

Active Remedy

78Remedial Technology (Soils Example) Table 5-2

Examples applicable to E85 impacts to vadose zone/capillary fringe

Active Remedy

Technology Benefits Limitations

In Situ T

reatment

Physical

Soil vapor extraction (SVE)

Soil

Rapidly removes readily strippable compounds (constituents with a high Henry's Law Constant, vapor pressure, and/or biodegradability). Promotes aerobic biodegradation of biofuels and methane oxidation (if present).

Not effective for constituents with a low Henry's Law Constant, vapor pressure, and/or biodegradability; may require ex situ vapor treatment.

Biological

Enhanced Aerobic Biodegradation

Bioventing - soil

Can result in rapid elimination of dissolved constituents and increase in dissolution and subsequent biodegradation of residual NAPL. Promotes methane oxidation. Likely inhibits formation of anaerobic conditions and methane generation.

Does not directly address LNAPL. High concentrations of some dissolved biofuel constituents (e.g. ethanol) can be toxic to microorganisms.

79Detailed Remedial Technology Tables (Tables 5-4a through 5-4c)

Biofuels evaluated• Ethanol (Table 5-4a)• Butanol (Table 5-4b)• Biodiesel (Table 5-4c)

Identifies targeted environmental media Evaluates technology by specific property (e.g. solubility) and

provides numerical values Compares efficiency to a reference petroleum hydrocarbon

compound Summarizes which compound (biofuel or reference

hydrocarbon) is favored by the remedial technology

Active Remedy

80Example Table 5-4a(Figure 5-2)

Expanding on the examples selected from Table 5-2 as applicable to vadose zone remediation of the E85 case study:

Technology Target Media P/C/B Properties Benzene Ethanol Favors

VZ GW SW

SVEX

Vapor Pressure

Aerobic Bio Potential

75 mm Hg

days

49 -56.6 mm Hg

hours

Benzene

Ethanol

BioventingX Aerobic Bio Potential days hours Ethanol

Depicts the media that the technology is applicable to

Describes what physical, chemical

or biological properties are affected by the

technology

Property values for benzene (reference

compound for ethanol)

Property values for

ethanol

Describes which compound the technology favors with respect to

the targeted property

Active Remedy

81

Example Table 5-4d (Methane)

Evaluates technology effectiveness on methane remediation versus methane generation

Technology Target Media P/C/B Properties Methane Remediation

Methane Generation

VZ GW SW

SVEX

Vapor Pressure

Aerobic Bio Potential

Applicable

Applicable

N/A

Inhibits

Bioventing X Aerobic Bio Potential Applicable Inhibits

Depicts the media that the technology is applicable to

Describes what physical, chemical or biological properties are affected by the

technology

Evaluates whether

technology can remediate

methane, and by which P/C/B

property

Specifies whether technology inhibits

methane generation, and by

which P/C/B property

Active Remedy

82Our Case Study: Long-Term Response Strategies

Application of SVE for vadose zone:• Physical removal • Enhanced biodegradation

Long-term monitoring for both soil gas and dissolved plume to assess and re-evaluate risk

Additional technologies can be evaluated/implemented CH4

83Long-Term Response Strategies Summary

Response strategies should be based on risks presented by biofuel release

MNA may be a viable response strategy If methane is a concern, longer-term monitoring

and/or engineering controls may be warranted Technology evaluation process can be applied to

biofuels, the petroleum component of the blend, and future biofuels

84

Training Roadmap


85

Our Case Study: Summary

Equipment compatibility issues

Biofuels fate & transport in the environment

Methane gas generation Site investigation design Monitoring in

environmental media Long-term response

strategies Risk management

CH4

86

Overall Summary

Biofuel production and consumption is increasing= increase in potential frequency of releases= potential for environmental impacts

By using the ITRC document, you will be prepared and able to:• Build a better Site Conceptual Model (SCM)• Understand fate & transport in the environment• Know how to investigate a biofuel release site• Formulate a better response strategy

87

Thank You for Participating

2nd question and answer break

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